There have been known a fiber-reinforced resin composition configured by impregnating a phenolic resin into cotton fabric used as a reinforcing base, or a fiber-reinforced resin composition configured by impregnating a resin composition, which is composed of a phenolic resin and polytetrafluoroethylene resin added thereto, into cotton fabric used as a reinforcing base (Patent Document 1). A multi-layered sliding contact component, configured by laminating the fiber-reinforced resin composition into a flat or circular cylindrical geometry, is excellent in wear resistance and load resistance, and also in rigidity. The sliding contact components are adopted to wear ring fitted to the outer circumferential surface of piston of hydraulic cylinder, underwater slide bearing and so forth. The phenolic resin exhibits superior performances under water lubrication, supposedly ascribable to the surface characteristics thereof. More specifically, possible reasons include readiness of adsorption of water to the cotton fabric used as the base, and good affinity of OH group of the phenolic resin with water.
The circular cylindrical multi-layered sliding contact component manufactured using the fiber-reinforced resin composition composed of the cotton fabric and the phenolic resin has, however, been facing difficulty in keeping a constant clearance (gap of sliding contact) with respect to the opposing shaft, due to swelling when used in a humid atmosphere or underwater. Such swelling of the circular cylindrical multi-layered sliding contact component is mainly ascribable to high water absorptivity of the cotton fabric used as the reinforcing base. Accordingly, low-water-absorptive synthetic fiber fabrics, composed of polyester fiber, polyacrylonitrile fiber and so forth, have attracted public attention as reinforcing bases other than the cotton fabric, intended for underwater applications. The synthetic resins having these advantages, however, still in need of improvement in adhesiveness to resins to be adopted, when used as the reinforcing base.
Patent Document 2 discloses a fiber-reinforced resin composition configured by using, as a reinforcing base, a woven fabric made of polyamide fiber, polyester fiber, polyacrylonitrile fiber or carbon fiber, and impregnated with a thermosetting synthetic resin such as phenolic resin added with fluorine-containing polymer, melamine resin, epoxy resin or alkyd resin, and a slide bearing using the same. It is also disclosed that, in order to improve the adhesiveness between these synthetic fibers and the synthetic resins, the synthetic resins are added with co-condensation products of polyamide and polyvinyl alcohol derivatives, as adhesion enhancers.
Patent Document 3 discloses a reinforced plastic plate configured by stacking sheets of polyester fiber woven fabric, used as reinforcing bases, after being impregnated with an unsaturated polyester resin. It is, however, difficult to adhere the intact polyester fiber to the unsaturated polyester resin, due to a poor content of functional groups in the polyester fiber. The Patent Document 3 therefore describes that, in order to improve the adhesiveness, or affinity, of the fiber with the resin, the polyester fiber is annealed with a bisphenol-based epoxy resin in an organic solvent, at a temperature of 150° C. or below for 5 to 120 minutes.